@woozle 

I edited the OpenVPN config file (added there Public IP from Huawei ONT) and now OpenVPN client is connected on my remote computer! It's great ! Thanks !!

By just typing "192.168.100.4" in web browser of my remote computer, I can open the web UI of my Router :))

One of the final goals to connect to router is to perform Wake on WAN (through Internet) on computer sitting behind this router. 

Now I can reach this router even if this computer is turned off, but is there a way to boot up this computer by sending a Wake on LAN magical packet from the Router? 

I searched in Archer A6 router menus, but I could not find something. 

I found this TP-Link article (https://www.tp-link.com/us/support/faq/2156/), but I'm not sure it's relevant - it's not clear for me if I should send the WoL magic packet from Router itself (but how?), or from my remote computer connected to router's VPN server through OpenVPN client. 

Maybe it will be needed to open a separate thread for that. 

Many thanks again for your advices! 

Note: Here a screenshot of OpenVPN client on my remote computer:

  @Louis81 

There are routers on the market that do have a built-in Wake on LAN feature in their user interface, but the Archer A6 does not. Therefore you will need to download one of the dozens of (free) software programs designed to send the Magic Packet and run it on the remote computer.

But like it says in the TP-Link article you've linked to, first "Make sure that the motherboard of PC A supports WOL." and "Make sure that the network card of PC A supports WOL.".

  @woozle many thanks for your answer !

Yes, in the motherboard of the PC A, the WOL is enabled.

So ok, I will try to follow this article (https://www.tp-link.com/us/support/faq/2156/) to configure Wake-on-Lan on my router Archer A6.

Many many thanks for all your help !!